Wind energy has been used for powering machinery since ancient times. Since then, the need to generate power from greener and renewable sources like the wind has become ever more urgent, and wind turbines have been developed for the production 10 of electrical power. In spite of this, wind power has seldom succeeded in commercial terms, owing to the variability of the supply of wind over time and geography. Typically, wind turbines operating in areas with consistently high wind speeds tend to be the most commercially viable, but such sites are rare.
Different wind turbine designs have been developed for use in different scenarios and applications. For example, they may be classified according to whether the blades of the wind vane rotate about an axis of a shaft which is horizontally or vertically disposed. Horizontal axis wind turbines (HAWTs) tend to be more commonly deployed as they tend to be more efficient: this is a result of blade rotation in a direction perpendicular to the direction of wind flow so that they receive energy through the entire cycle during rotation. However, they suffer various disadvantages, not least in the sheer height, size and weight of the towers and the blades, which makes installation, operation and maintenance extremely costly. They also need careful positioning into the wind, and are unlikely to work well in conditions where the wind is variable in speed and direction. Such wind turbines are also potentially disruptive, in the visual sense as well as to anything from wildlife, to the transmissions of radio signals.
Vertical axis wind turbines (VAWTs) are inherently less efficient as the blades receive energy from the wind for only a part of its rotation cycle during which it is “blown” forward. For much of the remaining part of the cycle, the blade rotates in a direction substantially against the direction of wind flow. There has been disclosure of use of guide vanes to better guide the wind flow to the blades to improve efficiency of the VAWTs. However, use of guide vanes with a planar surface often results on an amount of the wind impinging on the planar surface of the guide vanes being dispersed away from the intended direction of flow towards the blades. Therefore, there exists a need for a guide vane for addressing the foregoing problems.